At around this time every year we update the list of all those bird species recorded in the Channel Islands. Records will have been verified by each island’s ornithological committees. Where once birds may have been shot to confirm ID, records of new species and rarities became submitted through detailed notes and, today, they are often shown to us in high quality photos that leave little doubt about identification. We still like the notes.
Interestingly, while our overall bird list and those of the islands continue to increase, there have also been some species lost. We are always revising our opinions and, sometimes, we learn more about a species and question older records’ validity. Jersey’s first black-eared (in 1980) was scrubbed when we started to consider that it had almost certainly been a desert wheatear but that the observer was no longer confident. We also lose species to taxonomic splits.
As bird taxonomy becomes more and more detailed through use of some very fine, molecular level, ways of determining differences between species, we are often seeing traditional sub-species ‘elevated’ to species level. Then, that warbler for instance that we recorded but didn’t get a photo of may become several different warblers. But, which one was ours? Did we get sufficient detail noted to know which it was? You’ll see the problem in the full list. Especially in the warblers!
We also, well those of us of a certain age, grew up with a very set, long-established, view of the order that species occur in. We start with divers and grebes and end with crows. Well, actually that went out years ago as we learn more about relationships between birds and can even age when particular groups evolved. As a duck enthusiast, I’m pleased that they now rightly start off the CI List. They followed the pheasant, partridges and quail last year. So, species you are looking for may not always be where you expect them. They may also not be with old friends in the list and may have new company – have you got used to hawks and falcons not being related? Or that falcons and shrikes are next to each other in the list? And that grebes and divers aren’t closely related, and that crows are nowhere near the end?
So, back to the updated list. After being restricted to home over most of 2020, we began to travel again in 2021. However, the birds at home were still a draw it seems and records came in in good numbers.
We had two additions to the list which strangely went up by five! Guernsey’s Bonaparte’s gull in February and March and an October eastern olivaceous warbler in Jersey were the proper additions. The other increases came from re-organising warblers. However, as some of the older records of Bonelli’s and subalpine warbler are not identified to newer species, the list total could go down again in future.
Other notable birds were first ruddy shelduck and green-winged teal in Jersey (the former most likely from the establishing population in northern Europe) and a first rustic bunting in Alderney. Alderney saw their first corn crake in 43 years and first stone curlew in 134 years! Remarkably Alderney also saw their fourth great bustard in seven years, all from the UK reintroduction project, and the only bustards (of two European species) likely to have enjoyed their visit to the Channel Islands!
Breeding species continue to have mixed fortunes but it is very pleasing to note that short-eared owl bred in Guernsey and nightjars bred for a second year in Jersey.
And the individual islands’ totals? Jersey now has 340 recorded species, Guernsey 331, Alderney 308 and Sark 226.
This summer is proving to be a particularly hot one; one which we probably shouldn’t complain about! With rising temperatures and further limited rainfall though, the struggle for water supplies up at the Sorel aviary are beginning to show. At Sorel, it is clear how little rain we’ve received over the past month or so as the water butt, which is usually filled by Jersey’s plentiful rainwater, has been getting topped up by keepers. It may be physically challenging lugging water containers to the aviary in the recent heat but at least the choughs have clean water, and the keepers are becoming that little bit fitter! But, with rainwater being in short supply, lack of water wasn’t the only worry as the ground became hard and compact, potentially making foraging spots for choughs a little sparse; not an ideal start for the choughlets. Our Plémont pair Minty & Rey are normally rarely seen at the aviary but have been very frequent as of late; making us worry more about the state of foraging across the Island.
Bird flu, captive and wild bird devastation
The other worry on the Island is bird flu. So, what is bird flu? Bird flu is a type of influenza virus which is mainly spread amongst birds. The virus itself can be spread in two ways; directly (through contact) or indirectly (through faecal matter). It can affect mammals, but the risk is very low compared to the transmission between bird species. Bird flu was found on the Island in February this year and has caused quite a stir. This month, the number of cases seen across the Island has increased and the coasts are becoming scattered with many suspected avian flu fatalities, mostly seabirds. It is very important for us to state that the public must help prevent further spread by following the Government of Jersey Natural Environment guidelines and not picking up, touching or going near wild sick or dead birds. However, it is useful for the public to notify Natural Environment about any dead birds; especially if several dead birds are found in close proximity of each other. The most susceptible wild birds seem to be birds of prey, owls, wildfowl and seabirds. Notifying of dead birds will allow Natural Environment to test and confirm any new cases on the Island and set quarantine protocols. Although the photos below show herring gull fatalities across the cliffs at Devil’s Hole (which is very close to Sorel); we’re thankful to announce that the wild chough population is currently stable/unchanged.
Praising mother nature
The keepers couldn’t have been happier to see some much-needed rainfall and accompanying thunderstorms when they came, to clear away some of those high temperatures. We finally had a significant amount of rainfall. The ground around the aviary is still feeling pretty tough but at least it’s gained some form of hydration this month. Once we’d had a few days of rainfall, the grass in the aviary was looking a healthy green again after many months of looking very dried out and brown. But with rainfall comes plant growth, and it is truly amazing how much grass grows after a bit of rain! The keepers are now back into their routine of regularly mowing and strimming the grass inside and outside the aviary – hopefully giving the choughs another great foraging spot for tasty insects.
As we came closer to the end of August, the aviary became less ‘noisy’ as the youngest chicks belonging to breeding pair Bo & Flieur were becoming independent feeders. Less ‘choughlet’ begging behaviour at their parents and more wing-begging behaviours directed at the keepers! The young choughs are now arriving in their own little flock for the supplementary feed; it’s quite fantastic to see how they’ve learnt, grown and thrive, especially with all this hot weather. Although the feeds may have become quieter in regard to chick begging behaviour, there were still plenty of social hierarchy challenges amongst the young choughs and the adults. Plenty of scrabbles between siblings, young choughs of different parents as well as between some young choughs and adult pairs – the young choughs will soon find their place within the flock’s social structure.
Now that the young choughs are more independent; the parents are becoming less attentive. When the chicks started to feed for themselves the parent pairs would land on a food stand, allow their chicks to join and then move themselves to another stand; almost as if to give the young birds a fighting chance of a free meal before another more dominant pair took over the stand. However, now, the parent pairs will bat away any chicks, including their own! Since the aviary has become quieter, more pairs and other adults that have rarely been seen over the breeding and fledgling season became more frequent visitors such as Corbière pair Danny & Jaune. These two, along with other adults, have been known to avoid the aviary in fledgling season; and I don’t blame them, the choughlets are very noisy and demanding from anyone who will feed them!
In October, the European Parliament will vote on a report calling for an “EU cormorant management plan”. In plain text this means, controlling their population through lethal measures. Here are five reasons why this plan is not a good solution.
Seabirds are going to… eat fish. The aquaculture industry is mad at seabirds for foraging fish. Meanwhile, almost all our waters are overfished by humans, who are also wiping out fish habitats while they are at it. The cormorant diet consists of fish. It’s as simple as that. Just like bees feed on pollen and nectar. So, it’s obvious that, when they are out foraging, cormorants will be attracted to bodies of water where fish are abundant and easy to catch. Does that mean that some of them will be attracted to aquaculture facilities? Yes. Should they be killed because of this? Absolutely not. Science suggests that reducing the overall population of cormorants will not reduce conflicts at a local scale (i.e. aquaculture facility) – unless you put an enormous destructive effort on it. If a site is popular, whatever cormorants that are left, will continue to come back – no matter how well the population is “managed”.
Cormorants (great cormorant) almost went extinct in the 1970s due to human persecution and habitat loss primarily caused by humans. Thanks to the EU Birds Directive, as of 1979 it became illegal to disturb, capture, or kill them, as well as destroying their nests or robbing their nests. That, coupled with the reduction of water pollution and a ban on some dangerous pesticides has helped the great cormorant population bounce back across Europe in the past 30 years. Surely it would be a pity to undo all this great work just because cormorants like eating fish?
We’re ignoring the real problems. It is easy for industries to blame cormorants for the decline of fish population, but the reality is much more complex. The INTERCAFE research project showed that when cormorants are identified as a problem for fisheries there’s actually a whole range of reasons why fish production is in decline, including: invasive species, climate change, impoverished water quality, pollution, or the increase of algae in waters (aka eutrophication). In short, to produce fish, the restoration of natural habitats is key. Killing off cormorants won’t change anything – restoring the natural habitats of cormorants and fish, and sustainably managing wetlands, however, can provide part of the solution to these problems.
There are other solutions! The INTERCAFE project developed a toolbox with a wide range of management actions to reduce the vulnerability of fish to predation and deter cormorants from specific sites. This includes solutions to make sites less attractive to cormorants for nesting or feeding and measures to protect the fish (e.g. artificial refuges for fish, audible and visual deterrents for cormorants, nets and overhead wires, etc.) While there is no perfect measure that will work in every situation, all these techniques have been proven useful to reduce “conflicts” and deserve additional resources, such as from the new European Maritime Fisheries and Aquaculture Funds (EMFAF), to explore, develop and test them.
It’s really not so difficult. Just listen to the science. The ongoing discussion in the European Parliament on the “necessary management” of great cormorants is not based on the latest scientific consensus. The CormoDist project (endorsed by the Commission) clearly concluded that population management does not have an effect on specific site interactions. And it is not possible to know where the reduction of the population will have an impact.
In Jersey, cormorant is considered to be threatened and is RED on the local bird redlist. Despite seeming to be common, cormorants only nest in a very small number of sites and are vulnerable to disturbance and persecution. The rapid decline of the closely related shag, once a very common bird in Jersey, should serve as a salutary reminder of how fast a bird species’ fortune can change.
Chaffinch numbers dropped by 29% in the UK between 2008 and 2018, with a loss of 67% of the country’s greenfinches over the same period. As a result, greenfinch was moved on to the UK Red List in the most recent Birds of Conservation Concern assessment, published last year.
This new study used large-scale citizen science data and reveals that both species have declined in ways consistent with the impact of trichomonosis, a disease that was first detected in UK finches in 2005. Earlier work by the same organisations demonstrated that the disease had driven the decline in greenfinch populations – but the cause of the chaffinch’s decline, which began several years later, was unknown before now.
Scientists looked at patterns of change in greenfinch and chaffinch populations since the emergence of trichomonosis. They found that the declines were driven by a reduction in the survival of adult birds, a pattern that corresponds with the high levels of disease observed. A shift in recent years has seen trichomonosis diagnosed most often in chaffinches – previously it was diagnosed most often in greenfinches. This led the researchers to conclude that it was probably behind that species’ decline, too.
The joint BTO/IoZ study showed that survival rates of greenfinches and chaffinches were lowest in human-associated habitats. Disease transmission may be higher in these environments, where birds congregate at garden feeders. Trichomonosis makes swallowing difficult and can cause birds to regurgitate food, contaminating shared sources of food and water with their saliva.
Following best practice advice for feeding garden birds is recommended as a way to reduce the spread of disease. This includes regularly cleaning feeders and bird baths and, if possible, rotating the position of feeders around the garden to avoid build-up of food waste in one area. If sick birds are seen, temporarily suspending feeding will allow birds to disperse and may reduce the risk of transmission.
Other UK Red- and Amber-listed species, including house sparrow and bullfinch, are also susceptible to trichomonosis. Understanding the potential for the disease to spread to other species at bird feeding stations and working out how we can feed birds more safely are also priorities. Anyone can help us learn more about the diseases that affect garden birds by reporting sightings of sick or dead birds to the Garden Wildlife Health project, where you can also find best practice advice on feeding garden birds to help safeguard their health and welfare.
Dr Hugh Hanmer, BTO Research Ecologist and lead author on the paper, said: ‘Information derived from organised citizen science surveys has been vital to understanding what is happening to the populations of these two common bird species.
The results from our study put a spotlight on the use of supplementary bird feeding, both in gardens and as a conservation management tool, highlighting the importance of balancing the trade-offs between the positive conservation and engagement benefits of feeding with potential negatives of disease transmission that need to be better addressed.’
Dr Becki Lawson, ZSL IoZ co-author on the paper, said: ‘The emergence of trichomonosis in 2005 and dramatic declines of finches that have since occurred highlight the importance of understanding threats that affect the health of our garden birds and how disease can negatively affect biodiversity. We appeal to the public to continue to help us learn more about the conditions that affect garden birds, by reporting signs of ill health in garden wildlife to www.gardenwildlifehealth.org.’
Paper Habitat-use influences severe disease-mediated population declines in two of the most common garden bird species in Great Britain here
A successful start to the month: Catch ups! The start of July brought more ‘catch ups’ at the Sorel aviary. Great success as we caught five ‘choughlets’ in the space of two days – we really must have found them off guard! The most recent chicks in the ‘catch up’ belonged to Lee & Caûvette (one), Percy & Icho (one), Green & Pyrrho (two) and Bo & Flieur (two). Only three were left (see below).
Bidding farewell This month we said goodbye to our second valued team member for the chough project this year. Jane, a fellow chough enthusiast and a chough field volunteer with Durrell who has dedicated five years of her life to the chough project. It’s sad for her time to be over on the project, like the other staff and volunteers who have been involved in the past but, with time comes growth and new career opportunities. They may be relocating but I’m sure they will miss the chatter within our wild flock. If you are a chough enthusiast, don’t forget that you can help by reporting your sightings of any choughs seen around. Anthony Morin took these wonderful photos at Les Landes:
Harvest season There are eight species of small mammal in Jersey including four rodents. The choughs’ aviary is more active with rodents in different seasons of the year. At current, it is quite clear that, with all the harvesting being carried out in the surrounding fields, there is a greater abundance of rodent activity as of late. This can pose a problem through diseases they may carry and the holes they create around the overall structure of the aviary itself. A few of the small mammals that have been spotted in Sorel are protected under the Wildlife (Jersey) Law 2021 including the Jersey bank vole Myodes (Clethrionomys) glareolus caesarius, lesser white-toothed shrew Crocidura suaveolens and Millet’s shrew Sorex coronatus. The best way for us to keep the rodents out of the aviary is by reinforcing any entry and exits by repairing aviary netting, covering over holes and, the main factor, keeping any food at the aviary out of reach and/or secured in rodent-proof containers.
Drought This July, Jersey was officially considered to be in a drought. A drought in Jersey is confirmed by 15 consecutive days without measurable rainfall. The last measurable rainfall recorded occurred on Saturday 2nd July. Jersey is known for its limited underground reserves of water and no links to external water networks; therefore, it is important for Islanders to preserve water were possible. Anyone who is environmentally conscious will tell you that we should be using water wisely on a daily basis regardless of the weather; but it is even more important to when the Island is in a drought. There are many ways in which homeowners can reduce their water waste; here are some examples: • If its yellow, let it mellow – resist the urge to flush a toilet unless completely necessary • Taking shorter showers, using plugs in sinks to avoid running taps for long periods of time • Only using the washing machine and/or dishwasher when at full capacity • Not washing your car (including the ‘choughmobile’) or leaving sprinklers on the grass as often • Installing ‘low-flow’ equipment to all your water outputs • Fix your holey clothes instead of throwing them out for new plus shopping in charity shops.
Ok, scrap last month’s “hottest day of the year” Last month in Jersey we saw soaring temperatures of 33.1°C. However, on Monday 18th July, this was beaten by a scorching temperature of 37.9°! The highest temperature recorded in Jersey previously had been 36°C; this occurred 19 years ago. As summer is still in full swing, we worry what August’s temperatures will bring as things are only getting hotter with global warming. At the Sorel aviary we usually provide just the one water source for the choughs but with these rising temperatures, more water has been provided. The choughs, adults and chicks were all seen gular fluttering at the feed of the 18th; however, it was good to see that they were lining up next to the water trays to make use of the water provided in the aviary.
The last three chicks It was nearing to the end of the month, and we still had three more un-ringed chicks left to catch up. By this point in chick catch ups; the chicks are getting clever. The choughs know that, when two keepers come to the aviary, they need to be extra cautious, especially those that have been captured recently. But it brings me great joy to state that we caught the last three chicks all together, so now all the chicks that have fledged this year have been captured and colour ringed. We are scheduling a licensed ringer to place Jersey metal rings on the chicks sometime next month. We’ve not seen any more chicks arrive at the aviary now, so our fledged chick count for this year is a very respectable 16. Which is certainly nice as during our Ronez Quarry visit we only counted 14 chicks in the five accessible nests of our breeding pairs.
Table 1. A comparison of chicks found in nests at Ronez Quarry (plus one pair from Plémont), to the number of chicks that have fledged to the aviary this year.
A newly published study has estimated that the global great black-backed gull population has almost halved within the past four decades.
Using the most recent population counts from across the species’ range, Sam Langlois Lopez and his colleagues analysed population trends at a global, continental, and national scale between 1985 and 2021.
Their results confirmed recent concerns among conservationists that great black-backed gull has been faring badly at both local and regional scales, with widespread declines noted across its North American and European range. The global population is estimated to have declined by up to 48% over the study period from an estimated 291,000 breeding pairs in 1985 to 152,000-165,000 breeding pairs in 2021.
The losses have been most pronounced in North American populations, where the species may have declined by up to 68% since 1985. Although faring comparatively better, European populations have still decreased by up to 28% over the same period.
While there were populations that showed growth between 1985 and 2021, these tended to be smaller and/or were present within a larger state or country where most populations declined. Most increases were recorded in populations on the periphery of great black-backed gull’s range, or in areas that have been recently colonised. These include Spain, Germany and The Netherlands in Europe, as well as North Carolina and Virginia in the US.
The reasons for the decrease are not clear, although are suspected in part to be related to a reduction in the availability of discards from the fishing industry, as well as an overall decline in food availability in the natural environment.
As a result of the findings, Langlois and his colleagues recommend that great black-backed gull should be uplisted from Least Concern to Vulnerable on the IUCN Red List of Threatened Species under criterion A2 (an estimated reduction in population size of more than 30% over three generations).
Read Global population and conservation status of the Great Black-backed Gull Larus marinushere
The choughs greeted the keeper closer than ever! It’s quite clear at this time of year that the choughs recognise the keepers. They spot you on the walk up the coastal path towards the aviary, circling and vocalising loudly, following you along the foot path before finding a place to land. As you can see, the closest and safest spot was the entrance gate to the National Trust’s land. The choughs wing-begged and shouted, they really do know how to welcome their food providers!
Now is an even more important time than ever to be keeping up to date on our aviary maintenance. At this time of year, we are eagerly anticipating the arrival of ‘choughlets’ (chough fledglings) at the aviary. About four weeks after fledging, the chicks’ parents will stop feeding them so it’s essential for the chicks to watch their parents and learn how to forage for themselves. Choughs forage over coastal grasslands; they are often spotted in shorter grass fields, and this is because the insect abundance is generally higher where grass is short. Therefore, mowing the grass, strimming the hedgerows and neatening edges within and outside the aviary is important as it acts as a natural food source for the choughs and chicks that come to the aviary. Along with keeping the grass length short, we also provide ‘enrichment squares’; this is an added foraging obstacle which includes pinecones, slates and branches. These squares engage the choughs to lift and move objects to find the scattered insects – enabling them to work for their ‘free food’.
Is that a ‘choughlet’ I can see?!
Exciting news! We had our first ‘choughlet’ appearance at the Sorel aviary on 10th June! But there wasn’t just one chick, there were three! Our first sighting of the fledglings was in a field opposite the aviary – they were causing quite a stir in the flock. It wasn’t long until they flew in and landed on the aviary roof with Kevin & Wally. We assumed that these three must be theirs as they arrived together, and we had predicted this pair’s fledging dates back in May when we visited their nests to ring and age them! While monitoring the choughs at the aviary, it became clear that these three chicks were definitely from Kevin & Wally’s nest as we’ve witnessed many parent to chick feedings on top of the aviary. It wasn’t long, however, that more fledglings started arriving at the aviary. The next breeding pair’s chicks to arrive at the aviary belonged to Dusty & Chickay – four chicks on the 13th! Dusty & Chickay have always been pretty consistent with four chicks in the past; but it’s exciting to see the chicks that we saw in the nest arrive at the aviary happy and healthy!
Since those first arrivals, we’ve had Trevor & Noirmont’s chick, Manitou arrive at the aviary being very vocal, much like the majority of the chicks. It’s good to see the one chick we managed to ring at the nest arrive safely. By mid-month we started to see other breeding pairs bringing their chicks too, including Green & Pyrrho and Percy & Icho with their two chicks and Lee & Cauvette seen with one chick so far. It’s safe to say that the supplementary feeds at the aviary have been very loud and eventful this month! We may not have seen all of the chicks that were viewed at the quarry nests yet; we are still hopeful for more arrivals!
The past few weeks have been pretty hectic, but our former colleague Paul has been very useful in helping us monitor our chough activity in Ronez Quarry. We had our estimated fledging dates but hadn’t seen all chicks arrive at the aviary. But sure, enough there were plenty of chicks flying around the Sorel Lighthouse and quarry as acknowledged by Paul. The chicks will practice their flying before they are strong enough and brave enough to join their parents at the aviary for the supplementary feeds. We greatly appreciate the many chough enthusiasts that help us with our chough project; but don’t forget that anyone can help.
Follow this linkand you can do your bit by sending in public sightings of any choughs you see around Jersey Island!
Catch up time!
As the chough chicks keep arriving; it was time to take action and loosen up the hatch wires for the first chick ‘catch ups’ at the aviary. Why are we catching them up you ask? It’s to be able to identify each individual for monitoring with the use of colour-rings (which in turn allows us to know which breeding pair the chick belongs to through observations – see below), to indicate that they are owned and thrive in Jersey, to measure their bills, tarsus and weight. This is essential information we collect and keep records of for all the individuals in the wild free-flying flock. We haven’t needed to ‘catch up’ any choughs in quite some time so it took a few tries to loosen the hatch wires! But between the team, we’ve currently caught eight of the current fifteen chicks floating around with their parents.
Not something we want to see
One of Kevin & Wally’s fledglings had been limping since the first time it was seen arriving at the aviary. It was clear it had quite a large laceration to its left tarsus; but to be able to examine it properly we had to wait until the fledglings were more confident in going in and out of the aviary to carry out a ‘catch up’. We closely monitored the chick until we could catch it up within the aviary. On close examination it was clear how large the injury was but thankfully it had already scabbed over nicely and had no sign of infection, therefore, no additional action was needed. Fledglings are not always the most agile in flight and/or landing at first, something that is learnt over time. One can only assume that it crash-landed somewhere causing itself an injury. But one thing is for sure, it’s now a much better flier!
During these catch-ups we also quickly put the temporary, coloured plastic, rings on the chicks. We only have a short window of opportunity to see exactly which chick belongs to which pair of adults. After only a fairly short time, the chicks start to feed themselves, beg from their parents less and join groups of other juveniles. Groups who take great delight in begging from any passing adults (adults who aren’t fooled) and confusing the patient observer. As opportunities to catch newly arriving chicks inside the aviary are hard to predict, we do these catch-ups fairly randomly – often with long frustrating periods of watching a chick stare imploringly at their parents through the netting, through an open hatch, field etc and our sitting in the bracken or lying in a spot on a field that the sheep have only recently vacated. With everyone identified and, in a few weeks’ time, more likely to go into the aviary when we want them to, we will ask the licenced ringers from the Channel Islands Ringing Scheme to put permanent, numbered metal rings on.
Hottest day on record since 1894!
Between our catch ups, on Friday 17th June 2022, we had the highest June temperature in Jersey since records began in 1894. The temperatures hit a scorching 33.1 degrees Celsius. It’s not surprising that on this day most of the choughs were seen with their beaks wide open. This is because unlike most mammals; birds lack sweat glands and, therefore, they cool themselves down by keeping their beaks open. This is called ‘gular fluttering’ it is the avian equivalent of panting. Gular fluttering is just one of the few behaviours bird species express to stay cool in those hot weather days. Birds also submerge themselves in water either to swim and/or bathe. Sometimes you’ll catch a chough all wet and puffed up sitting on top of the aviary; this is their way of letting the breeze through their wet feathers to help them stay cool. As much as the choughs distinct jet-black plumage and striking red beak are beautiful; I do not envy them their plumage in that heat!
New research from BTO implicates rising temperatures in the steep decline of the willow warbler, one of the UK’s most tuneful harbingers of spring.
The study shows that willow warblers are doing better in Scotland, where temperatures are cooler. Evidence is building to suggest the population in southern Britain is a casualty of recent anthropogenic climate change.
BTO researchers used volunteer bird counts and habitat data from the BTO/JNCC/RSPB Breeding Bird Survey to separate the impacts of climate change and habitat change on willow warbler and chiffchaff populations. The analysis revealed that willow warbler numbers across the UK fell by 41% between 1994 and 2018, while those of the closely related chiffchaff grew by 133%. The picture was very different in Scotland, where temperatures are cooler than the UK average. North of the border, willow warblers increased by 77% and chiffchaffs by 244%.
During the period studied, the mean breeding season temperature was 12.7°C in England and 10.2°C in Scotland, close to the optimum breeding temperatures for chiffchaff (13.5°C) and willow warbler (11°C), respectively. However, UK Met Office data show that UK temperatures in the last 30 years have been about 1°C warmer than those during the three preceding decades. Changes like these can have impacts including producing a mismatch between young birds’ food requirements and insect abundance, an overall reduction in food abundance and shifts in habitat suitability.
The BBS habitat data showed that woodland and scrub, the preferred habitat for willow warblers and chiffchaffs, increased across the UK, with more habitat improvements in Scotland. However, this study showed that the increases in Scotland were more likely to be linked to climate change than habitat change.
Its UK decline means willow warbler has been on the Birds of Conservation Concern Amber List since 2002. With global temperatures forecast to keep rising, studies like this demonstrate the importance of long-term monitoring to ensure conservation measures are targeted effectively. More woodland and scrub, for example, would be more likely to be taken up by breeding willow warblers if it were concentrated in cooler areas of the UK.
Blaise Martay, BTO lead author on the paper, said: ‘We’ve discovered that these two superficially similar warblers have quite different temperature requirements during the breeding season. Climate change means willow warblers are now faring worse in warmer parts of the country, something that has implications for future conservation measures, such as habitat creation. The connection we’ve uncovered between temperature and breeding success suggests that conservation interventions for this species should be targeted in cooler parts of the UK.
She added, “I’d like to thank all the volunteers who take part in the BTO/JNCC/RSPB Breeding Bird Survey. Their records allow scientists like me to undertake analyses like this one and help us understand the pressures birds face as a result of climate change.’
In Jersey we have lost willow warbler as a breeding species although we still see birds in spring and autumn on migration. The annual north coast bird survey carried out in May or June each year when willow warblers and chiffchaffs would be nesting highlights the status of both these species. In Jersey, willow warbler is on the Red List.
See the abstract of Breeding ground temperature rises, more than habitat change, are associated with spatially variable population trends in two species of migratory bird here
Migratory birds are declining globally because of the way that humans have modified the landscape over recent decades – according to new research.
The new study reveals that population declines have been greatest among species that migrate to areas with more human infrastructure – roads, buildings, power lines, wind turbines – as well as higher population densities and hunting levels.
Habitat degradation and climate change have also played a part in driving long-term declines.
The research team hope their work will help inform how best to target conservation efforts. James Gilroy, from UEA’s School of Environmental Sciences, said: “We know that migratory birds are in greater decline than non-migratory species, but it’s not clear why.
“We wanted to find out where in their life cycles these migratory species are most exposed to human impacts.”
The team identified 16 human-induced threats to migratory birds, including infrastructure associated with bird disturbance and collisions, conversion of land from natural habitat to human land use, and climate change. Advances in satellite imagery allowed the team to map each of the 16 threats across Europe, Africa and Western Asia. The team also created the first ever large-scale map of hunting pressure across the region.
A total of 103 species of migrating birds were studied, including many rapidly declining species like turtle dove and the common cuckoo, using large-scale datasets.
The team calculated “threat scores” for factors such as habitat loss and climate change, across breeding locations, as well as non-breeding ranges. They then explored the relationships between these threat scores and bird population trends calculated from 1985 to 2018 by the Pan-European Common Bird Monitoring Scheme (PECBMS).
Claire Buchan from UEA, said: “One of the biggest impacts seems to be caused by things that would kill a bird outright – for example flying into a wind turbine, a building, being electrocuted on a powerline, hit by a vehicle or hunted. We found that exposure to these human-induced ‘direct mortality’ threats in the bird’s wintering ranges are reflected in population decreases in breeding birds.”
Aldina Franco, also from UEA, said: “Our findings are important because we need to understand where declining species are being most impacted by humans across their seasonal migrations. Pinpointing where birds are most exposed to these threats could help us target conservation actions.”
Download the paper Spatially explicit risk mapping reveals direct anthropogenic impacts on migratory birdshere
Jersey Island’s striking landscape shares many similarities with the Llŷn Peninsula in northwest Wales and the Iveragh Peninsula in southwest Ireland. Each of these regions are popular tourist destinations that are heavily influenced by agriculture and their connection to the sea. Their coastal landscapes are also extremely important to many forms of wildlife, not least our favourite corvid, the red-billed chough. The choughs’ iconic call, coupled with their bright red beaks and legs are a staple of the Llŷn and Iveragh Peninsulas. And these birds are clearly held in high regard on Jersey since their reintroduction in 2013.
On the Llŷn and Iveragh Peninsulas, choughs nest within mines, quarries, farm buildings and along cliff faces. A short distance from these nest sites, choughs have access to a mix of foraging habitats such as beach, sand dune, earth banks, coastal and agricultural grasslands, coastal heath and some well-grazed upland sites. Here, choughs can find their favourite food items such as beetles, ants and spiders, as well as the larvae of beetles, butterflies and moths. The importance of Llŷn and Iveragh for choughs is one of the primary reasons why ‘Special Protection Areas’ (SPAs) have been designated on both peninsulas.
The most recent national chough censuses indicated that chough populations across the UK and Ireland are relatively stable, although there were some concerning declines in certain regions. These national surveys are usually conducted every ten years in the UK. However, there was nearly two decades of a gap between Ireland’s 2002/03 national chough census and the most recent census carried out in 2021. Although these censuses provide invaluable insights into the health of national and regional chough populations, more frequent updates would help us determine how our choughs are faring in the years between censuses.With this in mind, the University College Cork-led LIVE Project, in collaboration with the National Trust in Wales and the Royal Society for the Protection of Birds (RSPB) organised a cross-border ‘Chough Count’ on the Iveragh Peninsula in southwest Ireland and the Llŷn Peninsula in northwest Wales on 12th March 2022. This initiative typifies one of LIVE’s main objectives – the sharing of knowledge and best practice between our two peninsulas.
The Llŷn Peninsula’s second ‘Chough Count’ saw 51 volunteers record 254 choughs as the sun shone in north Wales. Iveragh’s inaugural count saw twenty-six volunteers record 64 choughs in quite challenging weather conditions. By conducting annual counts of Llŷn & Iveragh’s choughs, we can detect trends in these populations in the years between censuses and we can identify important habitats for this protected species. The 2022 chough count also gave our surveyors the opportunity to record some of our other native birds such as skylarks, fulmars, white-tailed sea eagles and a hen harrier in Iveragh, as well as red kites, peregrine falcons and a green woodpecker on Pen Llŷn.
Distribution of records during Pen Llŷn’s second ‘Chough Count’ held on 12th March 2022.
The LIVE Project (ecomuseumlive.eu) has received funding from the European Regional Development Fund through its Ireland Wales cooperation programme. Led by the School of Biological, Earth and Environmental Sciences in University College Cork, LIVE works to enable the coastal communities of Llŷn and Iveragh to promote their natural and cultural assets, with the aim of encouraging more sustainable tourism opportunities in these rural regions of Ireland and Wales.